15 - Basic Pharmacologic Principles

Abstract

In the chapter on basic pharmacologic principles of the young developing child, we explain the tenets that underlie altered drug responses. We discuss the basic biologic, molecular, and mathematical concepts that apply to pharmacokinetics (drug absorption, distribution, and disposition) and pharmacodynamics (drug action through orthosteric and allosteric target modulation). We show how these concepts are further modified by pathology. The chapter is divided into four main sections: (i) principles of drug absorption and distribution; (ii) principles of drug elimination; (iii) clinical pharmacokinetics; and (iv) principles of pharmacodynamics. Despite the paucity of precise information on pharmacokinetic and pharmacodynamic profiles of many drugs in the newborn and young infant, the approach presented allows for greater understanding of age- and pathology-dependent altered drug responses and is supported by documented examples. Appropriate application of basic principles in pharmacology as well as adequate drug monitoring allows individualization of drug dosage and ameliorates treatment of neonates by reducing adverse drug effects.